It is well documented that isomaltose is a disaccharide with a low-sweetness, found in trace in some food products, e.g., fermented foods, which is obtainable in a substantial amount of up to 10-25 w/w % on dry solid basis (all percentages as used in the SPECIFICATION should mean "weight percentages on dry solid basis" unless specified otherwise) by reversible reaction with the use of acid catalyst or glucoamylase, glucose-transfer reaction of maltose or maltodextrin with the use of .alpha.-glucosidase (trans-glucosidase), or partial hydrolysis of dextran.
Early establishment of an industrial-scale and low-cost production of isomaltose material with the highest possible purity has been strongly anticipated because of the recent finding that isomaltitol, a hydrogenated product of isomaltose, is usable as a low-cariogenic and low-caloric sweetener.